• 센서학회지
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• 제33권1호
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• pp.34-39
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• 2024

Energy harvesting technology that converts the wasted energy resources into electrical energy is emerging as a semipermanent power source for self-powered electronics and wireless low-power sensor systems. Among the various energy conversion techniques, flexible piezoelectric energy harvesters (f-PEHs), using materials with piezoelectric effects, have attracted significant interest because they can harvest a small mechanical energy into electrical signals without constraints of time and space in various environments. In this study, we used a flexible piezoelectric composite film fabricated by dispersing BaHf_xTi_(1-x)O₃ (x = 0, 0.01, 0.05, 0.1) piezoelectric powders inside a polymeric matrix to facilitate f-PEHs. The fabricated f-PEH with optimal Hf contents (x = 0.05) generated a maximum output voltage of 0.95 V and current signal of 130 nA with stable electrical/mechanical disabilities under periodically bending deformations. In addition, we demonstrated a cantilever-type f-PEH and investigated its potential as a sensor by characterizing the output performance under mechanical vibrations at various frequencies. This study provides the breakthrough for realizing self-powered energy harvesting and sensing systems by adopting the lead-free piezoelectric composites under vibrational environments.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.205-214
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• 2019

This paper aims to discover factors and their influences degree to repurchase organic cosmetic in Vietnam. In addition, this research also discloses the main segments that have high demand re-buying intention based on demographic groups of gender, age, income, educational level, job, type of products, and place of production. Twenty-eight scale was designed based on previous studies and adjusted to match the 5-point Likert scale to conduct measurement. By using survey method to test hypotheses and set up conceptual models to collect 295 Vietnamese consumers who have experience in consuming organic cosmetic by explain the results through Smart PLS software. The findings show that there is positive attitude of customers to the intention of acquiring organic cosmetics, green perceived and customer satisfaction. In addition, customer satisfaction, knowledge of products, safety values, and environmental protection consciousness also play important roles to form a positive attitude of customers for products. Moreover, the consciousness of green living of consumers accounts for a high proportion in creating customer satisfaction for organic products. The results show useful information for current premises to determine the factors that influence the decision to repurchase organic cosmetic product, that provide business strategies.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.295-304
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• 2019

The study aims to investigate the determinant factors in the organisation of a firm's innovative activities, and the impact of innovation capability on firm's performance of electronic firms in Ho Chi Minh city, Vietnam. How is the performance of electronic companies after delivering an innovation project? How will innovation capability affect firm's performance in electronic companies? This study aims to seek the answer of these questions. We employ a Structural Equation Model and the PLS technique in order to validate the theoretical model proposed in this study. With observation of 374 valid firms, based on Cronbach's Alpha analysis, EFA analysis, CFA analysis and SEM analysis, this study discovers 5 groups of factors including: (i) Institution factors; (ii) Attitude of leadership factors; (iii) Marketing factors; (iv) Technological resources factors; (v) Combination factors, which have direct impact on innovation capability of firms. There are 4 groups of factors that have positive impacts on financial performance of electronic firms, with descending order of importance as follows: (1) Attitude of leadership factors; (2) Quality of human resources factors; (3) Innovation capability; (4) Marketing activities factors. Research results are important implications for Government administrative agencies for business to consult and introduce effective support policies.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.4113-4113
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• 2001

This study developed effective assay method of pharmaceutical quality control was developed by near-infrared spectroscopy (NIRS). The calibration equation model of assay was developed by 2nd deriviative PLS(Partial Least Squares) regression method with NIRS over the wavelength range from 1100 to 1400nm using diazepam tablets (2mg, 5mg). Although diazepam tablets are made by 5-different manufacture, they have similar formulation. When the correlation was compared with values by NIRS and HPLC, the R-2s and standard error of calibration (SEC) for 2mg were 0.9300 and 0.98%, the R-2s and SEC for 5mg were 0.9165 and 0.63%. The validation of the calibration equation model yield that the R-2s and standard error of prediction (SEP) for 2mg were 0.9611 and 0.995%, the R-2s and SEP for 5mg were 0.9114 and 0.842%. The method was validated on assay method for diazepam tablets by the calibration equation.

• 한국정보시스템학회지:정보시스템연구
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• 제18권3호
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• pp.89-110
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• 2009

In today's e-business environment, it is important to make decisions cooperatively between companies on a supply chain for their business success. This research analyzes empirically the influences of organizational factors on joint decision making and the ones of the joint decision making on business performance. We collected 188 corporate-level data through a Web survey and tested them statistically through PLS method based on a structured equation modeling. The results showed that (i) partner's knowledge creation capabilities, inter-organizational process modularity, and inter-organizational trust had direct effects on joint decision making, (ii) joint decision making and electronic business interfaces bad direct impacts on business performance. Contrary to our expectation, however, the moderating effects of electronic business interfaces between corporations on the relationship between joint decision making and business performance was not significant. On the basis of these results, we discussed theoretical and managerial implications of the findings. The results are expected to provide useful perspectives when companies establish strategies to improve capabilities of cooperative decision making and business performance.

• 대한의용생체공학회:의공학회지
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• 제18권4호
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• pp.381-388
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• 1997

본 논문은 환자 모니터링 시스템에서 환자 모니터, 중앙 환자 모니터, DB서버 그리고 임상 의사용 워커스테이션을 연결하기 위한 인터베드 통신망의 통신방식의 설계와 구현에 대해 기술하였다. 실시간 생체신호 모니터링을 위해 필요한 조건들을 바탕으로 각종 메시지 형식과 교환방식을 결정하였으며, 객체지향 설계기법을 적용하여 구현하였다. 현재, 인터베드 통신방식을 사용하여 구현된 서비스는 모니터링 중인 환자들에 대한 정보를 제공하기 위한 환자 위치 결정 서비스와 실시간으로 환자의 생체 신호 정보를 전달하기 위한 원격 환자 모니터링 서비스이다. 임상 현장에서 실험한 결과 이들 서비스들이 실시간 생체신호 모니터링에 필요한 조건들을 모두 만족하고 있음을 확인하였다.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1744-1749
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• 2018

This study investigated the feasibility of synthesizing GNPs using synchrotron radiation X-ray for use as a radiosensitizer in radiotherapy, and examined the morphology of the GNPs. Different concentration ratios of 4-mM gold precursor aqueous solution and 4-mM $NaHCO_3$ were mixed. This gold precursor aqueous solution was continuously irradiated with synchrotron radiation in the 4B X-ray microdiffraction beamline of Pohang Light Source (PLS)-II in Korea. The SEM, EDS, TEM, and XRD spectra of the GNPs synthesized using the synchrotron radiation were investigated. The GNPs synthesized using the synchrotron radiation were nanocrystals predominantly in the (111) direction of the face-centered cubic structure. We found that the shape of the gold nanoparticles was icosahedron at the molar concentrations of 0.25 mM:0.25 mM and 0.5 mM:0.5 mM mixed with 4 mM $HAuCl_4{\cdot}3H_2O$ and 4 mM $NaHCO_3$ solutions.

• The Journal of Asian Finance, Economics and Business
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• 제9권3호
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• pp.377-388
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• 2022

The Personal sense of uniqueness (PSU) is positively associated with subjective well-being and has been recently shown its correlation with happiness, influencing consumer's experience behavior. However, the effects of hedonic and eudaimonic experience on conspicuous and inconspicuous (consumer's need for status and inner fulfillment) are unknown. The purpose of this research is to address a gap existing in the literature by testing the effects of PSU on hedonic and eudaimonic leisure experiences and how happiness leisure experiences effects conspicuous and inconspicuous consumption. The relationships hypothesized in the model are tested using partial least squares structural equation modeling (PLS-SEM) and bootstrapping procedure. Data was gathered using a self-administrated survey, answered by 200 consumers based on consumers' leisure experiences. The findings of this study suggest that (i) PSU positively and significantly influence hedonic and eudaimonic happiness; (ii) the effect of PSU on eudaimonic happiness is higher than in hedonic happiness; (iii) eudaimonic happiness positively and significantly influence conspicuous and inconspicuous consumption; and (iv) hedonic happiness negatively and significantly influence conspicuous and inconspicuous consumption. This study helps fill a gap in the literature by introducing and testing the effect of hedonic and eudaimonic leisure experiences and the relationship between these constructs and PSU and (in) conspicuous consumption.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.5-13
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• 2011

In this study, seven Trichoderma species (33 strains) were classified using secondary metabolite profile-based chemotaxonomy. Secondary metabolites were analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS) and multivariate statistical methods. T. longibrachiatum and T. virens were independently clustered based on both internal transcribed spacer (ITS) sequence and secondary metabolite analyses. T. harzianum formed three subclusters in the ITS-based phylogenetic tree and two subclusters in the metabolitebased dendrogram. In contrast, T. koningii and T. atroviride strains were mixed in one cluster in the phylogenetic tree, whereas T. koningii was grouped in a different subcluster from T. atroviride and T. hamatum in the chemotaxonomic tree. Partial least-squares discriminant analysis (PLS-DA) was applied to determine which metabolites were responsible for the clustering patterns observed for the different Trichoderma strains. The metabolites were hetelidic acid, sorbicillinol, trichodermanone C, giocladic acid, bisorbicillinol, and three unidentified compounds in the comparison of T. virens and T. longibrachiatum; harzianic acid, demethylharzianic acid, homoharzianic acid, and three unidentified compounds in T. harzianum I and II; and koninginin B, E, and D, and six unidentified compounds in T. koningii and T. atroviride. The results of this study demonstrate that secondary metabolite profiling-based chemotaxonomy has distinct advantages relative to ITS-based classification, since it identified new Trichoderma clusters that were not found using the latter approach.

• The Korean Journal of Physiology and Pharmacology
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• 제17권6호
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• pp.517-523
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• 2013

Naphthyridine compounds are important, because they exhibit various biological activities including anticancer, antimicrobial, and anti-inflammatory activity. Some naphthyridines have antimitotic effects or demonstrate anticancer activity by inhibiting topoisomerase II. These compounds have been investigated as potential anticancer agents, and several compounds are now part of clinical trials. A series of naphthyridine derivatives were evaluated for their in vitro cytotoxic activities against human cervical cancer (HeLa), leukemia (HL-60), and prostate cancer (PC-3) cell lines using an MTT assay. Some compounds (14, 15, and 16) were more potent than colchicine against all three human cancer cell lines and compound (16) demonstrated potency with $IC_{50}$ values of 0.7, 0.1, and $5.1{\mu}M$, respectively. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used for quantitative structure-activity relationship (QSAR) molecular modeling of these compounds. We obtained accurate and predictive three-dimensional QSAR (3D-QSAR) models as indicated by the high PLS parameters of the HeLa ($q^2$, 0.857; $r^2$, 0.984; $r^2\;_{pred}$, 0.966), HL-60 ($q^2$, 0.777; $q^2$, 0.937; $r^2\;_{pred}$, 0.913), and PC-3 ($q^2$, 0.702; $q^2$, 0.983; $r^2\;_{pred}$, 0.974) cell lines. The 3D-QSAR contour maps suggested that the C-1 NH and C-4 carbonyl group of the naphthyridine ring and the C-2 naphthyl ring were important for cytotoxicity in all three human cancer cell lines.